Harris has recovered from a knee injury and could make his 100th appearance for the region while Fairbrother is available after serving a three-match suspension.
However, former Wales international Jarvis could miss the remaining months of the campaign after having surgery on a hamstring injury.
“It’s good to have Brok and Lloyd back so that is a boost for us,” said Jones. “On the other front, to lose Aaron and Brandon (Nansen) in similar circumstances is a blow to us.
“Both were trying to get over the ball so it does tempt you to tell them not to do it.
“But it’s done with the best intent, so wish them a speedy recovery as both were really hitting their straps and playing some good rugby for us. We will miss them.”
Meanwhile, Jones has indicated that Wales duo Ross Moriarty and Leon Brown will come into his thinking should they be released by Wales to play for the region.
Both players were named in a 39-man squad ahead of the Six Nations on Tuesday.
“Ross is seeing a specialist today (Tuesday) and I would be very thankful if Warren (Gatland) releases him to play for us," said Jones.
“Leon Brown is another one. It would be great to give him some game time with us rather than him going straight into a full international. But that will be the Welsh management’s decision.”
Dragons face another titanic European battle this Friday at Rodney Parade as they host the undefeated ASM Clermont Auvergne. CLICK HERE for advance price tickets and save money on match day prices.
It’s good to have Brok and Lloyd back so that is a boost for us,” said Jones. “On the other front, to lose Aaron and Brandon (Nansen) in similar circumstances is a blow to us
